1. Field of the Invention
The present invention relates to a waste solution treatment apparatus using a catalyst.
The waste solution referred to in this specification is a volatile waste solution which is difficult to volatilize at normal temperatures and contains a nonvolatile substance. For instance, an excess developing solution for electrophotography which contains nonvolatile substances such as a toner and the like and employs as a solvent a volatile liquid, such as isoparaffin, which is difficult to volatilize at normal temperatures. Or a developing solution for a wet process copying machine, a microfilm developing solution, a cleaner for automobiles, a cleaning fluid, a developing solution for an electrophotographic process, and a developing solution for magnetography, and other waste solutions that are produced after the use of various liquids having similar components.
2. Statement of the Related Art
In addition to the most commonly practiced process using silver halide, magnetographic processes and an electrophotographic processes are known methods of recording an image.
The magnetographic process is carried out as follows: First, a magnetic latent image is formed on a drum coated with a recording layer formed of a magnetic substance. A developing solution having hydrocarbon as a principal component is then applied to this magnetic latent image. In consequence, the magnetic latent image is developed into a visible image by a resin toner containing a powdered magnetic substance dispersed in the developing solution, and the image after being recorded is transferred to transfer paper, thereby obtaining a copy.
The electrophotographic process is implemented as follows: First, an electrophotographic film electrically charged and is then exposed to light so as to form an electrostatic latent image on the electrophotographic film. Then, a developing solution having hydrocarbon as a principal component and containing electrically charged toner particles is applied to the electrophotographic film so as to convert the electrostatic latent image into a visible image. After the electrophotographic film is dried, the image is fixed.
Thus, in both of these processes, a developing solution containing toner particles is used, resulting in an excess developing solution being produced when the developing solution is applied to the drum or the electrophotographic film. Accordingly, it is necessary to treat this excess developing solution in some way or another.
Accordingly, if an arrangement is provided such that the excess developing solution is recovered into a developing solution tank via a return pipeline so as to be used a plurality of times, it becomes unnecessary to provide treatment immediately. However, if this measure is adopted. there is a drawback in that the arrangement of the apparatus becomes complicated. Moreover, even if the excess developing solution is used a plurality of times, the fatigued excess developing solution must be unavoidably treated as a waste solution eventually.
For this reason, as a method of treating such a waste solution, a method has been proposed in which a lower end of a core composed of a bundle of fibers, or the like, is immersed in the waste solution. The volatile liquid in the waste solution is allowed to move to an upper end of the core by means of the capillary phenomenon, and the volatile liquid is burnt (oxidized) by using a catalyst provided upwardly of the core. According to this method, since the aforementioned waste solution has hydrocarbon as a principal component, a major portion of the waste solution can be converted to carbon dioxide and water. Since no flame is produced during combustion, this method is very favorable in terms of safety and the designing of the apparatus.
However, it has become clear that, with the above described method using the core, in the case of a waste solution containing a nonvolatile substance such as the aforementioned toner, the nonvolatile substance adheres to the surface of the core in the form of tar and consequently prevents the rise of the volatile liquid. As a result, the volatile liquid is burnt insufficiently or ceases to burn at all within a short period of time. Hence, with this method, it is difficult to burn the waste solution continuously and completely.
In addition, as developing solutions such as those mentioned above, liquids whose boiling point is substantially higher (150.degree.-200.degree. C. or thereabouts) than a normal temperature (15.degree. C.) are used to ensure safety, the developing solutions are very difficult to volatilize at a temperature close to room temperature. Accordingly, if an attempt is made to cause the volatile liquid in the waste solution to volatilize and burn the same in a state of vapor, it is necessary to heat the waste solution.
However, if heating is continued throughout the combustion, the energy cost associated with the apparatus becomes very large. In addition, since a measure must be provided to prevent the apparatus itself from reaching an abnormally high temperature by taking into account the radiation of resultant heat, the manufacturing costs of the apparatus increases significantly.